The Refrigerant Cycle
The diagram below in illustration shows the refrigerant system state in each component on this vehicle.
| Item | Description |
|---|---|
| 1 | High pressure liquid |
| 2 | Low pressure liquid |
| 3 | High pressure vapor |
| 4 | Low pressure vapor |
The BCM monitors the evaporator temperature sensor thermistor as air is passed through the evaporator core and the SOBDMC controls the A/C electric compressor speed. If the temperature of the evaporator core discharge air is low enough to cause the condensed water vapor to freeze, the BCM sends a message to the SOBDMC. The SOBDMC responds by reducing the speed of the A/C electric compressor.
The high-side line pressure is monitored so that A/C electric compressor operation is interrupted if the system pressure becomes too high or too low (low charge condition).
The A/C electric compressor has internal thermal protection in the ACCM to interrupt compressor operation if the compressor exceeds temperature limits.
The A/C electric compressor pressure relief valve opens and vents refrigerant to relieve unusually high system pressure.